Cell Imaging with BioAFMs

PeakForce Tapping provides the lowest force measurement available in a biological AFMs which preserves the integrity of soft, biological samples during imaging. The precise force control of PeakForce Tapping allows the resolution of very soft, flexible living cell structures that are easily deformed by lateral dragging methods.

PeakForce Tapping on the BioScope Resolve has enabled researchers to obtain the first images of cell surface structures, believed to be microvilli on the surface of living cells. The two MDCK cell images shown were obtained by Dr. Hermann Schillers on the BioScope Resolve using only 10pN of imaging force. Cell surface structures can be seen in the images.

Microvilli are microscopic cellular membrane protrusions that increase the surface area of cells while minimizing any increase in volume and are involved in a wide variety of functions, including absorption, secretion, cellular adhesion, and mechanotransduction. While AFM has previously been used to obtain images of microvilli on fixed cells, to our knowledge, this is the first time microvilli have been resolved on living cells. The difficulty in resolving these structures on living cells is due to their very soft, flexible structure that protrudes from the cell surface. These structures can be easily deformed or pushed around by the AFM probe unless very low imaging forces, such as those enabled by PeakForce Tapping mode, are used. When imaging forces are increased above the 10pN used to measure the MDCK cells the microvilli can no longer be seen.